Calling device



Patented Sept. 2, 1924.

UNITED STATES PATENT OFFICE.

NOEL I-I. LYSONS, OF MONTREAL, QUEBEC, CANADA, ASSIGNOR T0 WESTERNELECTRIC COMPANY, INCORPORATED, 0F NEW YORK, N. Y., A CORPORATION OFNEW,YORK.

CALLING DEVICE.

Application filed May 24, 1922. Serial No. 563,185.

To all whom t may conce/m:

Be it known that I, NOEL I-I. LrsoNs, a subject of the King of England,residing at Montreal, Province of Quebec, Canada, have invented certainnew and useful Improvements in Calling Devices, of which the followingis a full, clear, concise, and exact description.

This invention relates to calling devices and particularly to impulsetransmitters employed in automatic and semi-automatic telephone systemsfor the purpose of controlling the operation of switching mechanism.

In automatic telephone systems it is necessary to allow a certainminimum time interval between the last impulse of a series sent by acalling device and the first impulse of the next series in order topermit the switch ing mechanism to distinguish between successivedigits.` This interval must be of as long a duration as the maximum timerequired for the automatic hunting operation of the switches at thecentral ofiice. In the usual type of calling device, a period of delay,after the group of impulses for each digit is sent, is secured by reasonof the necessity of resetting the device for the next digit. It has beenfound by experience, however, that this period is not always suficient,particularly when the resetting movement is small, as in the case of thelower digits.

The object of the invention is to provide an impulse transmitter withsimple and ecient means for insuring the proper time interval betweenthe transmission of successive series of impulses in order to preventfalse connections from being made.

The invention provides means, such as an arm integral with the motorspring and controlled by the main shaft of the dial, for removing theimpulse springs from the control of the interrupter mechanism after therequired number of impulses has been transmitted and at a definite timeinterval before themechanism reaches its normal position. In thedrawing, Fig. 1 is a front view of a calling device embodying theinvention;

Fig. 2 is a rear view; Fig. 3 is a side View; n Figs. 4 to 8, inclusive,show in successive stages, the operation ofthe impulse springs of thecalling device; and

Fig. 9 shows a modiiedarrangement of springs in a position correspondingto Fig. 4; and

Fig. 10 is a fragmentary view of a detail of the device. y

The dial plate or finger wheel 1 is fixed to a shaft 2rotatablysupported in a base plate 24. A spring 25 serves as a motorspring for driving the shaft. On the under side of the dial plate 1 issecured a pawl 27 which is arranged to engage with the ratchet 28carried by the gear member 5, which meshes with the pinion. 6. On thesame shaft as the pinion 6 is the butterfly cam or interrupter 3 and thegear 7, the latter of which drives the governor 4. The relation of thepawl and ratchet 27 and 28 is such that when the finger wheel isrevolved in a clockwise direction, referring to Fig. 1, the gear 5 isnot rotated. When the finger wheel is subsequently released, it isreturned to its normal position by means of the motor spring 25, andduring its return movement, the pawl 27 engages ratchet 28 and,therefore, causes the rotation of the interrupter 3 and the governor 4,all as disclosed more in detail in U. S. Patent No. 1,279,352 ofSeptemberl 17, 1918, to A.. E. Keith.

On the interrupter cam shaft 'is secured a. collar 30, having twodiametrically disposed notches or recesses 31; mounted on the plate 24is a bent leaf spring 32 with lits free end arranged to engage one ofthe notches 31 when the interrupter cam is in normal position; theposition of the vspring is such that when the cam 3 and collar 30 rotatein a counter-clockwise direction (as viewed in Fig. 2),.the spring 32 isdepressed and the collar30 rides Nover it, and if there is a tendency torotate in the opposite direction, the side wall of one of the recesses31 meets the end of the spring 32 and further movement is prevented.

Contact spring set 10, mounted on the rear of the base plate 24,comprises the springs 11, 14, 15, and 16. The arrangement of the springsis such that spring 14 tends to move toward spring 16 and makes contacttherewith, and impulse spring 11 tends to move away from spring 15 andto bring its end 12 into the path of rotation of interrupter 3. However,when the finger wheel 1 is in normal position, as shown'in Fig. 1,finger 13 carried on the inner end of the shaft 2, bears 'upon ytheupper surface 14" near the free end of the spring 16 and'holds it"lawa'yfrom spring 16 and lagainst spring 11,"`whi`chin`-turn is'heldagainst spring 15, making contact therewith and holding its outer end 12out of the path of the interrupter 3. The arm 13, in the form shown inthe drawings, is an insulated vextensin of, the motor spring 25. y l

1Iii-practice, the VContact'spring 15 will lbe connectedby a suitableconductor 44 to one side of fthe' "subscribers line, while lthe springs11 and `l1'4, which aretied together, willbe conductively connected tothe other side '40'through the subscriber@ receiver 41 and transmitter42. Spring 16 will be lconducftiyely connectedfto the second side ofthesubscribers line in'shunt of the 'receiver .41.- Therefore, whenth'e.springs are inthe position shown in Figsf4and 8 of the drawingfthelcircuitwill be Closed through the subseribers telephone instruments.

llvllienv Jthe Isubscriber ydials 'the yfirst digit `by rotating thengerwheel in a clockwise directiomthe lvarm`13 will be moved inthedireetion'of the arrow, inFig. 4, and will, therefore, `after a shortmovement, release the spring 1,4,- which will thereupon rise and makeContact with spring 16, thereby shiuiting the sul'oscribers receiverduring the dialing operation, as is common practice. Thev release 'ofspring 14 also results in 'the -partial release of spring 11. Spring 11,however, is` permitted to move only a short distance `when it is stoppedby the contact of its outer end 12 with a wing of the interrupter 3 Thismovement of springll is not sluiiicient f to breakits contactwith spring15. As soon as thelinger wheelv is released and-starts. on its returnmovement,

the .interrupt-er '3` is rotated as Adescribed .above and intermittentlyreleases and de- -presses the spring 11,-(Figs-6 and 7) vthusalternately breaking and making its contact with spring 15 and,therefore, sending outv impulses over the line and eiecting theselective Ioperation of a switching device at the Acentral eXchangein awell-known manner.

l i Since itis l'the ycustom of the callingsubscriber to immediatelyreset the dial, the second series of impulses is frequently begun beforeconnection has been completed at the central exchange to a switch thatis free,V toV respond to its impulses, withthe resultjthat there is anincorrect settingy of the switches.I In the present device, the dialplate 1, andthereforetheinterrupter 3, continue to-y rotate for a,substantial period,

when the required number yof impulses has tained during the entirerotation rofthe .in-

terrupter 3 and no impulses are sent over the line. As the dialcontinues to rotate, arm 13 moves invthe direction of the arrows shownin Figs. 7 VVand 8, and finally when the dial plate reaches its normalrelation, the parts assume the position shown in'Fig. 8, which is thesame as thatshownin'Fi'g; 4. rlhe dial will now'be reset'for the nextseries ofy impulses and the sequence Vof operations shown in Figs. '4to8fwill'be repeated. There is, thus, added tothe interval re quired forresetting the rvdial ari-"interval equal to the time which is occupiedfby'the dial in moving through an anglesuflicient to bring theinterrupter 3 lto the position shown in Fig.' S. iThe length ofthis'period will depend upon the length'of bearing'surface '14"of`thespring 14. A period equivalent tofthat required for sending two'impulseshas been found to give satisfactry results. y y y p The modificationshown in ig. "9 is adapted to be usedwitha circuitsimilarto that shownin 'UQ S. VPatent LNo."1,353,612, September 21, l1920, to F- N. Reeves.Spring 15 willbe connected to'one side 43 of the line. VSpring 20 willvbe connected throughthe receiver`49 to the" same sideof vthe line.Springs 11 an'd 16, which'are electrically tied .'togetlier, will beconnecte'd'to the other side ofthe line` through "the transmitter 46.Spring' 14I will be connected to said other side 45 of theline Yinshiintof the transmitterfl when thesubstation circ-uit' is yready'forI thecalling Idevice to be operated. Spring 16 is adapted to cooperate withIspring 14 to close .a pathfalternate 'to the^path through spring f2()and the receiver. Spring 11 ispr'ovided with an insulatedlmember 22 toprevent electrical connection betweenfit and sprii1g`14. l

What is claimed is: n s y f 1. InI an impulse sending device,`a.ingerwheel for setting said fd'evice, Contact springs, *an interrupter forsaid `contact springs, a motor yspring for operating-,said device, andmeans integral with said'mlotor spring for removing said contact springsfrom the control of' said interrupten' 2. In anaimp'ulse sending device,a linger wheel for setting said device, a plurality of contact springs,an -interrupterV in operative relation to one of said contact' springs,a motor spring, an arm integral withsaid motor spring in operativerelation topan- "rac other of said Contact springs and controlled motorspring in operative relation to anby said finger Wheel for removing saidother of said Contact springs and controlled 10 springs from the controlof said interrupter. by said finger Wheel for removing said 3. In animpulse sending device, a finger springs from the control of saidinterruptor` Wheel for setting said device, a plurality of ln Witnesswhereof, I hereunto subscribe Contact springs, an interrupter inoperative my name this seventeenth day of May,. relation to one of saidContact springs, a A. D. 1922. motor spring, an arm integral with. saidNOEL H. LYSONS.

